1. Technical Field of the Invention
The present invention relates to a grinding method employed in a vertical type of double disk surface grinding machine for simultaneously grinding an upper surface and a lower surface of a work to be ground which is held by a work holding jig by means of a pair of vertically movable upper and lower grinding wheels.
2. Prior Art
As an example of quantitative grinding implemented by the vertical type of double disk surface grinding machine, the Applicant of the present invention has developed a method in which a current value of a motor for rotating the grinding wheels is measured and grinding start positions of the grinding wheels are set in response to a variation of the current value. More specifically, the grinding wheels are made to approach the work while the current value of the motor for rotating the grinding wheels is being measured, and when an increase of the current value reaches a set value after the grinding wheels come into contact with the work, relevant positions are memorized in a controller or the like as the grinding start positions, and the upper and the lower grinding wheels are temporarily retreated to standby positions. Then, the two grinding wheels are fed again at a high speed to positions immediately before the grinding start positions after the grinding wheels detect the grinding start positions and retreat, and the speed is lowered to a grinding speed so that the grinding operation of a predetermined grinding allowance is implemented at the grinding start positions.